The serious looming energy crisis, the dependence on foreign energy sources of most countries, such as Spain, which has already reached 80%, the excessive consumption of homes today exceeding 40% of the total energy used by societies and the preoccupying effects caused by the change in climate, have made housing a top priority for governmental institutions, for example Directive 2002/91/EC of the EUROPEAN PARLIAMENT and COUNCIL.
If the energy demand for heating and cooling of homes is not substantially reduced without further delay, the Kyoto agreement will not be complied with and the change in climate will not be detained.
Heating and cooling of homes today are supported on two essential, complementary and mutually needed points. The first point consists of installing good thermal insulation in enclosures and roofs, while at the same time extensively using lightweight materials in partitions, noggings, roofs, and the like. Structures are thereby economized and transport and on-site installation costs are saved. Nevertheless, even by giving priority to thermal insulations, the waste of energy in homes will continue because there are other determining factors involved, as will be seen below.
The second point relates to the installation of mechanical equipment in conventional homes, generally heat pumps, which provide hot or cold air, depending on the season. However, when the operation of this equipment is stopped or brought to a halt, homes cool down or heat up in a short period of time. It is then clear that these two points or concepts complement one another and meet their objectives at the cost, however, of high energy consumption by means of permanently operating. However, since there is no economy that can resist permanent equipment consumption nor is there sufficient energy to supply them, one must ask what the purpose of thermal insulation and lightweight materials is.
What happens actually corresponds to a somewhat anarchic process in which there are several factors involved. First, like it or not, conventional homes lack air tightness, i.e. it is rather easy for outdoor air to enter and for air from the house to exit due to cracks or irregularities in the closure or the fit of doors and windows, in addition to directly opening same or chimneys and air vents in kitchens and bathrooms; there is even a number of mechanical air extractions. However, the main cause of these movements of air is the difference in pressures between the inside of the house and the outside. Therefore, the exit of a certain volume of air from the house causes a certain pressure drop in the indoor air, which causes the necessary entrance of the same volume of air from outdoors to balance the air pressure of the house with the outside atmospheric pressure. All this occurs within a set of different, changing outdoor and indoor temperatures which cause different densities, vertical movements and movements of all types, giving rise to a truly natural and permanent renewal of air in conventional houses, and although it serves a good purpose, i.e. it eliminates bad smells and provides oxygen to be breathed in, it fosters a truly wasteful energy model, since the air entering the house enters with the energy provided thereto from outdoors and the exiting air pulls out all the energy contained in the house. Therefore this is a throwaway energy model that is widespread today.
This air renewal in conventional homes is further verified in any case regardless of whether or not mechanical heating and cooling equipment is installed, which equipment frequently recycles the inside air by artificially incorporating heat or cold, but such equipment does not normally mechanically introduce outdoor air into homes except in certain installations that would enhance natural renewal of the air in the house.
Furthermore the total volume of air in a house is renewed between once and several times every hour, depending on the climate and the country. It is a widespread problem that must be solved. It is obvious that, from the point of view of physics, conventional homes have been reduced to simple containers of air, to passive spectators in an energy play in which they do not actively participate because they lack the ability to be involved therein since their materials are determined according to their thermal insulation and light weight, qualities that are not suitable for collecting and transmitting energy in the form of heat.
The described throwaway energy model is the main cause of waste in homes today. Any variants in conventional systems such as radiators or panels mean the same in the end because they need to permanently emit energy since the house barely participates in the process.